Method for making serrated-head bolts



United States Patent METHOD FOR MAKING SERRATED-HEAD BOLTS J. Philip Lehning, Chicago, lll., assignor to International Harvester Company, a corporation of New Jersey Application June 22, 1955, Serial No. 517,114

1 Claim. (Cl. 10-27) This invention relates to a greatly simplified method for making a bolt head having an integrally formed washer on the under side thereof and a peripherally serrated upper portion adapted to fit a box type or socket type wrench. More in particular this invention relates to a method of forming such a bolt head as a flash-free finished product from a blank in a single punch and die operation.

Most all of the commonly known types of bolts are provided with square cut or hexagonally cut longitudinally disposed iiat faces adapted to engage a wrench for application of torsional stress thereto. Where the head portions of such bolts are not provided with an integrally formed washer on the shank or underside thereof, the head may be satisfactorily formed by the shearing action of a single punch and die operation. However when such bolts are provided with integrally formed washers on the underside of the head portion, the deformation or displacement of material during a punch and die operation is excessive which leaves an outwardly flared ash portion usually at the lower extremities of the liat faces and the upper extremity of the integrally formed washer. The resulting flash portion is not only waste metal but also at least one subsequent and expensive operation is required to remove the flash to complete the finished product.

Particularly for use with larger type bolt heads box type and socket type wrenches are provided with as many as twelve V-shaped engaging grooves or notches disposed on the inner periphery thereof to expand the versatility thereof. Thus wrenches of this type may be used where as little as a 30 degree rotational movement of the engaged bolt head is permissible before re-engagement of the wrench may be required.

With the above described problem in mind it is therefore an object of this invention to provide a new and useful bolt with a head having a plurality of V-shaped serrations or notches disposed on the outer periphery thereof adapted for engagement with a box type or socket type wrench.

Another object of the invention is to provide a bolt having a head according to the preceding object wherein an integrally formed washer is disposed on the under side of the head.

A further object of the invention is to provide a bolt with an improved head having a plurality of V-shaped longitudinally extending serrations wherein the serrations terminate in a V-shaped facet formation adjacent the upper edge of an integrally formed washer disposed on the underside of said bolt head.

A still further object of the invention is to provide a method of making bolt heads according to the preceding objects whereby the finished bolt head including an integral washer on the underside thereof may be completed in a single punch and die operation.

A still further object of the invention is to provide a method of making bolt heads from blanks according to the preceding objects whereby the head is formed withlCC out loss of material and with minimum displacement of material.

Further objects and advantages of the invention will be apparent from the following description, the appended claims with the accompanying drawings wherein:

Figure l illustrates a bolt blank having a head blank and a shank without threads.

Figure 2 is a vertical cross-sectional View, partly broken, illustrating a punch and die positioned in a press including a bolt formed from a bolt head blank.

Figure 3 illustrates a bolt with a finished head after ejection from the punch and die operation of Figure 2.

Figure 4 is a plan view of a finished bolt head showing the profile of the serrations or notches.

Referring to Figure 1 the numeral 10 illustrates a bolt shank having a reduced end portion 11 adapted for cutting threads thereon. Y At this point it should be understood that the shank portion 11 may be threaded or unthreaded prior to the formation of the bolt head according to this invention. A solid cylindrically shaped bolt head blank 12 is integrally connected to the other end of the shank 10 as shown in Figure l. The construction material used in this bolt may be of metal or non-metal material as may be appropriate.y

Figure 3 illustrates a nished bolt with the portion 11 of the shank 10 threaded. The finished bolt head generally indicated at 13 is provided with a top surface 14 and a plurality of peripherally disposed serrations or notches 15 in a V-shaped cross-sectional formation as shown in Figure 4. The number of notches 15 uniformly disposed about the periphery of the head may number three or more but generally speaking standard type box wrenches or socket wrenches are adapted to engage bolt leads having four, six or twelve faces depending usually upon the size of the head.

In order to facilitate engaging a wrench to the bolt head a circular chamfered portion 16 which intersects the upper end portions of the notches 15 with the top surface 14 is provided.

On the underside of the head 14 there is provided an integrally connected washer 17 with the head 13 and shank 10. The washer 17 may be annularly shaped as shown in Figure 3 but of course it may also be serrated on the outer periphery as well as being serrated on the underside thereof. The washer 17 may optionally be provided with an annular shoulder portion 18 as shown in Figure 3.

In order to form the notches 15 with minimum displacement of material as well as improving the structural strength of the bolt head 13, facets 19 are provided. The facets 19 are mostly comprised of displaced material during the forming thereof as described later. Each of the facets 19 is disposed in a plane at an angle with reference to the longitudinal axis of the bolt. Two edges of each facet are formed by the juncture of the lower respective ends of the corresponding notch 15. The third edge of each facet 19 is formed by the juncture of the facet with the upper edge of the outer periphery of the washer 17 as best shown in Figure 3.

From the foregoing it may be readily seen that a new and novel type of bolt head having an integrally connected washer on the underside thereof which is adapted for use with commercial type wrenches has been described. Further, this particular type of bolt head lends itself to a unique method of manufacture whereby the bolt head 13 may conveniently be formed by forcible displacement of material in a single punch and die operation which method will now be described.

Referring to Figure 2 the numeral 20 shows a portion of a ram of a press (not shown) having a recessed portion 21 adapted to support for vertical movement a punch or forming member 22. The punch 22 is provided with a vertically disposed bore 23 adapted to receive the shank of the blank bolt or work piece generally indicated at 24, The lower portion of the punch 22 is adapted t0 form the underside of the washer 17. For convenience Figure 2 illustrates a shallow annular recess 25 in the punch 22 for forming the optional annular shoulder portion 18 ofthe washer 17 The numeral 26 illustrates a portion of the bed plate of the press (not shown) provided with a recess 27 adapted to position a die 28. The die 28 comprises a cavity or hollow portion generally indicated at 29. It can be seen from Figure 2 that the upper periphery 30 of the cavity 29 is adapted to form the washer 17 of the finished bolt head 13. The portion 31 of the cavity 29 below the upper periphery 30 is adapted to form the lower end portions of the notches and the facets 19 of the bolt head 1 3. The intermediate portion 32 of the cavity 29 is provided with serrations 33 which are adapted to form the notches 15 of the bolt head 13. It will be noted that the intermediate portion 32 of the cavity 29 flares outwardly in a downward direction to facilitate ejection of the linished bolt head 13 from the die 28.

Referring to Figure 2 it will be seen that the punch 22 and die 28 are in closed relation just after the formation of a bolt head 13 from the blank 12. The force exerted in a downward direction by the ram with the punch 22 causes sufficient pressure on the head blank 12 in the zone above the line A-A of Figure 2 in the cavity 29 of the die 28 resulting in deformation or displacement of the material adjacent the curved surface of the head blank 12 to rst form the charnfered portion 16 followed by the formation of the notches 15. The excess material resulting from the formation of the chamfered portion 16 and notches 15 is crowded or owed to form the facets 19 and washer 17.

From the above it can be seen that a bolt head blank 12 with its associated shank 10 may be inserted in the punch 22 and the punch 22 driven downwardly by the ram 20, the pressure exerted against the head blank 12 will in but a single strike convert the head blank 12 by deformation of the material into a bolt head 13. It may also be seen that if the head blank 12 is of a correct predetermined volume or diameter in relation to longitudinal length, no ash of excess material will occur on the annular surface 34 where the lower extremity of the punch 22 approaches the upper surface of the die 28, Thus if the volume of the head blank 12 is properly controlled with respect to its cross-sectional diameter and length the finished bolt head 13 will be substantially of the same volume as the blank 12. Further if the volume of the blank 12 is properly controlled the bolt head 13 will be in finished product form upon its removal from the punch and die thus eliminating the expensive necessity of adding a separate operation to remove ash formation.

From the foregoing it can readily be seen that a unique bolt head construction has been described as well as a convenient and economical method of producing the same.

The invention may berermbodied in other specic forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the specific foregoing description, and all changes which come within the meaning and range ofequivalency of the claim appended are therefore intended to be embraced therein.

What is claimed is:

The method of making in a single stroke punch and die operation a linished flash-free metal bolt head of the kind described consisting of the steps of taking a bolt shank provided with an integrally connected solid metal cylindrically shaped head blank of predetermined height and diameter, applying pressure downwardlyfin an axial direction to the upperv end of the peripheral portion of said blank, continuing the application of said pressure to said blank in an axial direction downwardly in sufcient magnitude to-displace a portion of said metal in an axial direction without displacing metal adjacent the lower end of said blank to f orm a plurality of uniformly spaced peripherally disposed notches extending longitudinally from said upper end and terminating at a distance substantially above said lower end, said displaced metal substantially being formed into facets positioned at the bottom end of each of said formed notches and integrally connected to a remaining annular shaped portion of said blank whereby a finished hash-free bolt head is formed having a mean diameter and height substantially equal to the height and diameter ofl said blank,

References Cited in the le of this patent UNITED STATES PATENTS 662,134 Rodd Nov. 20, 1900 721,659 Blakeslee Mar. 3, 1903 1,933,737 Kaufman Nov. 7, 1933 2,102,941 Cadwallader Dec. 21, 1937 2,133,466 Purtell Oct. 18, 1938 2,333,388 Poupitch Nov. 2, 1943 2,353,531 Whitney July 11, 1944 2,689,359 Friedman Sept. 2l, 1954 FOREIGN PATENTS 436,706 Great Britain Oct. 16, 1935 747,937 Germany Oct. 20, 1944 1,001,909 France Feb. 2, 1952 

